man2html: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/man2html - from package: man

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/man2html - from package: man2html-base

You may install the required package with command apt-get install {package}

Error in other languages:
man2html: bevel nie gevind nie
man2html: comandă negăsită
man2html: comando não encontrado
man2html: commande introuvable
man2html: command not found
man2html: käsku ei ole
man2html: không tìm thấy lệnh
man2html: komanda nerasta
man2html: Kommando nicht gefunden.
man2html: kommandot finns inte
man2html: komut yok
man2html: nie znaleziono polecenia
man2html: níor aimsíodh an t-ordú
man2html: no se encontró la orden
man2html: no s'ha trobat l'ordre
man2html: opdracht niet gevonden
man2html: parancs nem található
man2html: perintah tidak ditemukan
man2html: príkaz nenájdený
man2html: příkaz nenalezen
man2html: команда не найдена
man2html: командата не е открита
man2html: 命令找不到
man2html: コマンドが見つかりません